package test_9_20;

public class Seven_28 {
	public static void main(String[]args) {
		int sum=0;
		int i=0;
		for(i=13;i<=1003;i+=10)
		{
			int k=i;
			if(i/10%2==0)
			{
				k*=-1;
			}
			sum+=k;
		}
		System.out.print(sum);
	}
}
